Gas distribution for chemical vapor deposition/infiltration

ABSTRACT

A gas distribution plate for a chemical vapor deposition/infiltration system includes a body having a first side and a second side opposite the first side. The body may be hollow and may define an internal cavity. The gas distribution plate may also include a plurality of pass-through tubes extending through the internal cavity, a cavity inlet, and a plurality of cavity outlets. A reaction gas may be configured to flow through the plurality of pass-through tubes and a gaseous mitigation agent may be configured to flow into the internal cavity via the cavity inlet and out of the internal cavity via the plurality of cavity outlets to mix with reaction gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, claims priority to and thebenefit of, U.S. Ser. No. 15/709,338 filed Sep. 19, 2017 and entitled“GAS DISTRIBUTION FOR CHEMICAL VAPOR DEPOSITION/INFILTRATION,” which isincorporated herein by reference in its entirety for all purposes.

FIELD

The present disclosure relates to composite manufacturing, and morespecifically, to gas distribution devices for chemical vapordeposition/infiltration systems and methods.

BACKGROUND

Carbon/carbon (C/C) composites are used in the aerospace industry foraircraft brake heat sink materials, among other applications. Siliconcarbide (SiC) based ceramic matrix composites (CMCs) have found use asbrake materials and other components in automotive and locomotiveindustries. These composites are typically produced using, for example,chemical vapor infiltration (CVI) or chemical vapor deposition (CVD).Such processes generally include placing porous preforms into a reactorand introducing a gaseous precursor to form silicon carbide depositionswithin the pores of the preform.

However, conventional infiltration and/or or deposition processes resultin byproduct deposits accumulating within system components of themanufacturing system, such as the exhaust piping. The byproduct depositsmay be reactive and even pyrophoric, and thus precautions are warrantedto promote a safe manufacturing environment. For example, conventionalmanufacturing systems are often shut-down for periods of time whileusers manually clean the components and piping of the manufacturingsystem to remove the byproduct deposits. This cleaning procedureincreases the downtime of the manufacturing system and thus decreasesthe capacity and throughput of conventional ceramic matrix compositemanufacturing systems.

SUMMARY

In various embodiments, the present disclosure provides a gasdistribution plate for a chemical vapor deposition/infiltration system.The gas distribution plate includes a body having a first side and asecond side opposite the first side, according to various embodiments.The body may be hollow and may define an internal cavity. The gasdistribution plate may further include a plurality of pass-through tubesextending through the internal cavity, with each pass-through tube ofthe plurality of pass-through tubes extending from a first openingdefined in the first side of the body to a second opening defined in thesecond side of the body. A reaction gas may be configured to flowthrough the plurality of pass-through tubes. The gas distribution platemay further include a cavity inlet defined in the body and a pluralityof cavity outlets defined in the second side of the body. A gaseousmitigation agent may be configured to flow into the internal cavity ofthe body via the cavity inlet and the gaseous mitigation agent isconfigured to flow out the internal cavity via the plurality of cavityoutlets.

In various embodiments, the reaction gas in the plurality ofpass-through tubes is isolated from the gaseous mitigation agent in theinternal cavity. In various embodiments, the plurality of cavity outletsare distributed among the second opening of the plurality ofpass-through tubes. In various embodiments, the gas distribution platefurther includes a plurality of static mixing features extending fromthe second side of the gas distribution plate, wherein the plurality ofstatic mixing features facilitates mixing of the gaseous mitigationagent with the reaction gas. Each static mixing feature of the pluralityof static mixing features may be “T” shaped.

In various embodiments, the body includes a conical distribution featureprotruding into the internal cavity from the second side of the bodyopposite the cavity inlet. In various embodiments, a footprint of theconical distribution feature on the second side of the body is solid. Invarious embodiments, the plurality of cavity outlets and the secondopening of the plurality of pass-through tubes are disposed outward of afootprint of the conical distribution feature on the second side of thebody.

Also disclosed herein, according to various embodiments, is a system ofmanufacturing a ceramic matrix composite component. The system mayinclude a chamber having an inlet portion and an outlet portion, whereinthe inlet portion is configured to house a porous preform. The systemmay also include a first inlet for introducing a gaseous precursor intothe inlet portion of the chamber, a gas distribution plate disposedbetween the inlet portion and the outlet portion of the chamber, and asecond inlet for introducing a gaseous mitigation agent into an internalcavity defined in the gas distribution plate. The gas distribution platemay facilitate mixing the gaseous mitigation agent with a reaction gasfrom the inlet portion of the chamber. The system may further include anexhaust conduit coupled in fluidic communication with the outlet portionof the chamber.

In various embodiments, the gas distribution plate includes a pluralityof pass-through tubes, wherein the gas distribution plate facilitatesmixing the gaseous mitigation agent with the reaction gas from theplurality of pass-through tubes. The gas distribution plate may be afirst gas distribution plate, and the system further may further includea second gas distribution plate. The second gas distribution plate maybe disposed between the first gas distribution plate and the outletportion of the chamber. Accordingly, the internal cavity may be a firstinternal cavity and the second gas distribution plate may includedefines a second internal cavity, wherein the gaseous mitigation agentis configured to sequentially flow through both the first internalcavity and the second internal cavity before mixing with the reactiongas. In various embodiments, the second inlet is configured to introducethe gaseous mitigation agent into the first internal cavity via a firstcavity inlet. The gaseous mitigation agent may be configured to flowfrom the first internal cavity to the second internal cavity via aplurality of second cavity inlets extending between the first gasdistribution plate and the second gas distribution plate. In variousembodiments, the first cavity inlet is a central conduit and theplurality of second cavity inlets are offshoot conduits that arepositioned around the central conduit.

In various embodiments, the second gas distribution plate is disposedbetween the inlet portion of the chamber and the first gas distributionplate. The second gas distribution plate may include a second pluralityof pass-through tubes, and the second inlet may include a pass-throughconduit that extends through the second gas distribution plate and isconfigured to introduce the gaseous mitigation agent into the internalcavity via a cavity inlet. In various embodiments, the pass-throughconduit is a central conduit and the cavity inlet is one of a pluralityof cavity inlets, wherein the plurality of cavity inlets are offshootconduits that are positioned around the central conduit.

Also disclosed herein, according to various embodiments, is a method ofmanufacturing a ceramic matrix composite component. The method mayinclude introducing a gaseous precursor into an inlet portion of achamber that is configured to house a porous preform and introducing agaseous mitigation agent into an internal cavity of a gas distributionplate disposed between the inlet portion and an outlet portion of thechamber that is downstream of the inlet portion of the chamber. Thegaseous mitigation agent may be configured to mix with a reaction gasdownstream of the gas distribution plate. The gaseous precursor mayinclude methyltrichlorosilane (MTS) and the gaseous mitigation agent mayinclude hydrogen gas.

The forgoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exemplary aircraft having a brake system, inaccordance with various embodiments;

FIG. 1B illustrates a cross-sectional view of a brake assembly, inaccordance with various embodiments;

FIG. 2 is a schematic flow chart diagram of a method of manufacturing aceramic matrix composite, in accordance with various embodiments;

FIG. 3A is a schematic view of a ceramic matrix composite manufacturingsystem, in accordance with various embodiments; and

FIG. 3B is a schematic view of a ceramic matrix composite manufacturingsystem having a gas distribution plate, in accordance with variousembodiments;

FIG. 4 is a schematic flow chart diagram of a method of manufacturing aceramic matrix composite, in accordance with various embodiments;

FIG. 5A is a perspective cross-sectional view of a gas distributionplate, in accordance with various embodiments;

FIG. 5B is another perspective view of the gas distribution plate ofFIG. 5A, in accordance with various embodiments;

FIG. 6 is a cross-sectional view of a gas distribution plate, inaccordance with various embodiments;

FIG. 7A is a perspective cross-sectional view of a system having two gasdistribution plates, in accordance with various embodiments;

FIG. 7B is another perspective view of the system of FIG. 7A, inaccordance with various embodiments; and

FIG. 8 is a perspective cross-sectional view of a system having two gasdistribution plates, in accordance with various embodiments.

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical changes and adaptations in design andconstruction may be made in accordance with this disclosure and theteachings herein without departing from the spirit and scope of thedisclosure. Thus, the detailed description herein is presented forpurposes of illustration only and not of limitation.

Provided herein, according to various embodiments, is a manufacturingsystem(s) and associated method(s) for chemical vapordeposition/infiltration processes, such as may be utilized in thefabrication of ceramic matrix composite components. The disclosedsystems and methods generally mitigate the formation and accumulation ofharmful/hazardous byproduct deposits. While numerous details areincluded herein pertaining to aircraft components, such as brakecomponents, the manufacturing system(s) and method(s) disclosed hereincan be applied to fabricate other ceramic matrix composite componentsand to other chemical vapor deposition/infiltration processes.

Referring now to FIG. 1A, in accordance with various embodiments, anaircraft 10 may include landing gear such as left main landing gear 12,right main landing gear 14 and nose landing gear 16. Left main landinggear 12, right main landing gear 14, and nose landing gear 16 maygenerally support aircraft 10 when aircraft 10 is not flying, allowingaircraft 10 to taxi, take off and land without damage. Left main landinggear 12 may include wheel 13A and wheel 13B coupled by an axle 20. Rightmain landing gear 14 may include wheel 15A and wheel 15B coupled by anaxle 22. Nose landing gear 16 may include nose wheel 17A and nose wheel17B coupled by an axle 24. In various embodiments, aircraft 10 maycomprise any number of landing gears and each landing gear may compriseany number of wheels. Left main landing gear 12, right main landing gear14, and nose landing gear 16 may each be retracted for flight. Thelanding gear may extend from an underside of the fuselage 28 or from anunderside of the wings 30.

Aircraft 10 may also include a brake system which may be applied to awheel of a landing gear. The brake system of aircraft 10 may comprise acollection of units, assemblies, and subsystems that produce outputsignals for controlling the braking force and/or torque applied at eachwheel (e.g., wheel 13A, wheel 13B, wheel 15A, wheel 15B, etc.). Thebrake system may communicate with the brakes of each landing gear (e.g.,left main landing gear 12, right main landing gear 14, and/or noselanding gear 16), and each brake may be mounted to each wheel to applyand release braking force on one or more wheels. The brakes of anaircraft 10 may include a non-rotatable wheel support, a wheel (e.g.,wheel 13A, wheel 13B, wheel 15A, wheel 15B, wheel 17A, and/or wheel 17B)mounted to the wheel support for rotation, and a brake disk stack.

Referring to FIG. 1B, brake assembly 110 may be found on an aircraft, inaccordance with various embodiments. Brake assembly 110 may comprise abogie axle 112, a wheel 114 including a hub 116 and a wheel well 118, aweb 120, a torque take-out assembly 122, one or more torque bars 124, awheel rotational axis 126, a wheel well recess 128, an actuator 130,multiple brake rotors 32, multiple brake stators 34, a pressure plate36, an end plate 38, a heat shield 140, multiple heat shield sections142, multiple heat shield carriers 144, an air gap 146, multiple torquebar bolts 148, a torque bar pin 151, a wheel web hole 152, multiple heatshield fasteners 153, multiple rotor lugs 154, and multiple stator slots156.

Brake disks (e.g., interleaved rotors 32 and stators 34) are disposed inwheel well recess 128 of wheel well 118. Rotors 32 are secured to torquebars 124 for rotation with wheel 114, while stators 34 are engaged withtorque take-out assembly 122. At least one actuator 130 is operable tocompress interleaved rotors 32 and stators 34 for stopping the aircraft.In this example, actuator 130 is shown as a hydraulically actuatedpiston. Pressure plate 36 and end plate 38 are disposed at opposite endsof the interleaved rotors 32 and stators 34.

Through compression of interleaved rotors 32 and stators 34 betweenpressure plate 36 and end plate 38, the resulting frictional contactslows, stops, and/or prevents rotation of wheel 114. Torque take-outassembly 122 is secured to a stationary portion of the landing geartruck such as a bogie beam or other landing gear strut, such that torquetake-out assembly 122 and stators 34 are prevented from rotating duringbraking of the aircraft. Rotors 32 and stators 34 may be fabricated fromvarious materials, such as ceramic matrix composites. The brake disksmay withstand and dissipate the heat generated from contact between thebrake disks during braking.

In various embodiments, and with reference to FIG. 2, a method 290 ofmanufacturing a ceramic matrix composite component, such as a brakedisk, is provided. The method 290 may include utilizing themanufacturing apparatus and manufacturing system 305 disclosed herein,as described in greater detail below with reference to FIGS. 3A and 3B.In various embodiments, and with reference to FIGS. 2 and 3A, the method290 includes introducing a gaseous precursor into an inlet portion 312of a chamber 310 at step 292 and introducing a gaseous mitigation agentinto an outlet portion 313 of the chamber 310 at step 294, according tovarious embodiments. The inlet portion 312 of the chamber 310 houses oneor more porous preforms 315, made from carbon or silicon carbide (SiC)fibers. The porous preforms 315 may be loaded into the inlet portion 312of the chamber 310, which may be a reactor furnace or other reactioncompartment. Generally, the introduction of the gaseous precursor atstep 292 results in densification of the porous preforms 315 and theintroduction of the gaseous mitigation agent at step 294 shifts thereaction equilibrium to disfavor the formation of harmful and/orpyrophoric deposits, which can accumulate in the exhaust conduit 340that is coupled in fluidic communication to the outlet portion of thechamber 310, as described in greater detail below.

The gaseous precursor may be introduced via a first inlet 320 into theinlet portion 312 of the chamber 310 and the gaseous mitigation agentmay be introduced via a second inlet 330 into the outlet portion 313 ofthe chamber 310. In various embodiments, these two steps 292, 294 areperformed simultaneously to fabricate ceramic matrix compositecomponents. In other words, both the gaseous precursor and the gaseousmitigation agent may be flowing into the respective portions 312, 313 ofthe chamber 310 during fabrication. Accordingly, in various embodiments,the inlet portion 312 of the chamber 310 is upstream of the outletportion 313 of the chamber 310.

In various embodiments, the gaseous precursor is introduced via thefirst inlet 320 at an inlet upstream side 311 of the inlet portion 312of the chamber 310 and the gaseous mitigation agent is introduced viathe second inlet 330 into an outlet upstream side 314 of the outletportion 313 of the chamber 310. In various embodiments, because thegaseous mitigation agent is introduced into the outlet portion 313 ofthe chamber 310, the gaseous mitigation agent may not directly interactwith the fibrous/porous preforms 315 and thus may not directly affectthe reaction chemistry, as described below, in the inlet portion 312 ofthe chamber 310. Instead, the gaseous mitigation agent generallyconditions the effluent gas flowing from the inlet portion 312 toinhibit and/or mitigate the formation of harmful byproduct deposits inthe exhaust piping (e.g., exhaust conduit 340), according to variousembodiments.

In various embodiments, the respective flow rates of gaseous precursorand gaseous mitigation agent are different. Introducing the gaseousprecursor at step 292 is performed at a first flow rate (e.g., a firstmolar flow rate, which refers to the number of moles per unit time thatpasses through an area) and introducing the gaseous mitigation agent atstep 294 is performed at a second flow rate (e.g., a second molar flowrate). In various embodiments, the second molar flow rate is betweenabout 50% and about 300% higher than the gaseous precursor flow rate inthe first stream. In various embodiments, the second molar flow rate isbetween about 100% and about 200% higher than the gaseous precursor flowrate in the first stream. In various embodiments, the method 290includes controlling the temperature and pressure within pressurizingthe chamber 310 to specific values. For example, the method 290 mayinclude heating the chamber 310 to above 1,000 degrees Celsius (1830degrees Fahrenheit) and may include maintaining the chamber 310 at 10torr (1.33 kilopascal).

The gaseous precursor includes, according to various embodiments, one ormore reactants/reagents that react within the inlet portion 312 of thechamber 310 and infiltrate the pores of the porous preforms 315 todensify the porous preforms 315. For example, the gaseous precursor mayinclude methyltrichlorosilane (MTS), dimethyldichlorosilane ortrimethylchlorosilane, among others. The MTS may decompose in responseto being introduced via the first inlet 320 into the inlet portion 312of the chamber 310 and, via various intermediate reactions, may resultin SiC deposits forming inside the pores of the porous preforms 315.Additional details pertaining to illustrative reactions that occurduring the infiltration and deposition process are included below. Thegaseous precursor stream may also include hydrogen gas, according tovarious embodiments. In various embodiments, the MTS constitutes about5% of the gaseous precursor stream. In various embodiments, the gaseousmitigation agent is hydrogen gas.

In various embodiments, the reaction pathway that occurs within thechamber 310, with MTS and hydrogen gas constituting the gaseousprecursor and with hydrogen gas constituting the gaseous mitigationagent, includes the following reactions:CH₃SiCl₃→.SiCl₃+.CH₃  Equation (1).SiCl₃+.CH₃→SiC+3HCl  Equation (2).CH₃+H₂→CH₄+.H  Equation (3).SiCl₃+CH₃SiCl₃→HSiCl₃+Cl₃SiCH₂.  Equation (4)CH₃SiCl₃→Cl₂Si═CH₂+HCl  Equation (5)HSiCl₃→:SiCl₂+HCl  Equation (6)CH₃SiCl₃→ClCH₃+:SiCl₂  Equation (7):SiCl₂+CH₄→:ClSiCH₃+HCl  Equation (8)ClCH₃+H₂→CH₄+HCl  Equation (9)

As mentioned above, the gaseous mitigation agent introduced at step 294of the method 290 interacts with the effluent from the inlet portion 312of the chamber 310 (i.e., interacts with the gaseous stream exiting theinlet portion 312 after passing over and through the porous preforms315). In various embodiments, the gaseous mitigation agent shifts thereaction equilibrium of the above listed equations to disfavor theformation of harmful and/or pyrophoric deposits in the exhaust conduit340. That is, the gaseous mitigation agent alters the stoichiometricratios of the various/intermediate reactions to mitigate the formationof harmful byproducts which can accumulate within the exhaust conduit340 of the system 305.

In various embodiments, the harmful byproduct deposits thatconventionally form in the exhaust conduit are, for example,polychlorosilanes and cyclic carbosilanes that result from the freeradicals and double bonded intermediate species produced in theequations above. Said differently, by using hydrogen gas as the gaseousmitigation agent, the “extra” hydrogen gas introduced at step 294 intothe outlet portion 313 of the chamber 310 may drive production of HClvia Equation (9), and which may shift the reaction equilibrium todisfavor the formation of the free radical and double bond intermediatespecies formed in Equations (5), (6), and (8).

While numerous details are included herein pertaining specifically tousing MTS as the gaseous precursor and hydrogen gas as the gaseousmitigation agent, other compounds may be utilized. For example, invarious embodiments, the gaseous precursor may be dimethyldichlorosilaneor trimethylchlorosilane, among others. In various embodiments, thegaseous mitigation agent may include water vapor, NH₃ gas, BCl₃ gas, orair, among others.

In various embodiments, and with reference to FIG. 3A, the system 305,which may be a chemical vapor deposition/infiltration apparatus, mayinclude a first supply conduit 322 and a second supply conduit 323. Thefirst supply conduit 322 may deliver the gaseous precursor from a sourceto the inlet portion 312 of the chamber 310 via the first inlet 320. Thesecond supply conduit 323 may deliver the gaseous mitigation agent froma source to the outlet portion 313 of the chamber 310 via the secondinlet 330. A first valve 327 may be coupled to the first supply conduit322 to control flow of the gaseous precursor and a second valve 328 maybe coupled to the second supply conduit 323 to control flow of thegaseous mitigation agent. In various embodiments, the system 305 mayalso include a purge valve 329 that is configured to control flow of apurge gas, through one or both of the first and second supply conduits322, 323, into the chamber 310 for purging the chamber after a completedCVD process.

In various embodiments, the second supply conduit 323 may extend intoand through the inlet portion 312 of the chamber 310 to deliver thegaseous mitigation agent to the outlet portion 313 of the chamber 310.That is, the second inlet 330 may be an outlet end of the second supplyconduit 323. In various embodiments, the second supply conduit 323extends through the first inlet 320. For example, the second supplyconduit 323 may extend into the chamber 310 so as to deliver the gaseousmitigation agent to a central, upstream section of the outlet portion313 of the chamber 310. In various embodiments, the second inlet 330 isdefined and disposed in a side wall of the chamber 310.

In various embodiments, the inlet portion 312 of the chamber 310 of themanufacturing system 305 may include one or more retention spacers 316for retaining one or of the porous preforms 315. In various embodiments,the retention spacers 316 may facilitate distributing the porouspreforms 315 throughout the inlet portion 312 of the chamber 310. Theretention spacers 316 may be porous themselves, thus further allowingsufficient infiltration and deposition. In various embodiments, thechamber 310 may include one or more gas distributors 318 that facilitatethe mixing and distribution of the gaseous precursor flowing through thehoused porous preforms 315. The gas distributors 318 may also functionto divide the inlet portion 312 into sub-compartments.

In various embodiments, the outlet portion 313 of the chamber 310 maydefine a gas mixing space 319 that may house a gas mixing substrate(e.g., a reaction sub-chamber). The gas mixing space 319 may facilitatemixing of the effluent gas from the inlet portion 312 with the gaseousmitigation agent introduced into the outlet portion 313 via the secondinlet 330. The gas mixing space 319 may include a porous substrate. Invarious embodiments, the gas mixing space 319 may be loaded with a gasmixing substrate, such as volcanic rock or graphite, among othermaterials.

In various embodiments, and with reference to FIG. 3B, a gasdistribution plate 500 (schematically depicted in FIG. 3B) may beutilized to facilitate intermixing of the gaseous mitigation agent withthe reaction gas that is produced via the densification of the porouspreforms (e.g., the reaction gas is the resultant gas from a chemicalvapor deposition/infiltration system). As mentioned above, themitigation agent generally shifts the reaction equilibrium to disfavorthe formation of harmful and/or pyrophoric deposits, which canaccumulate in the exhaust conduit 340 that is coupled in fluidiccommunication to the outlet portion of the chamber 310. Accordingly, byimproving the extent of intermixing between the gaseous mitigation agentand the reaction gas, the formation of harmful and/or pyrophoricdeposits can be further disfavored. In various embodiments, the gasdistribution plate 500 is disposed between the inlet portion 312 and theoutlet portion 313 of the chamber 310.

Generally, and with reference to FIG. 4, a chemical vapordeposition/infiltration method 490, such as a method of manufacturing aceramic matrix composite component, includes introducing a gaseousprecursor into the inlet portion 312 of the chamber 310 at step 492 andintroducing a gaseous mitigation agent into an internal cavity 514(FIGS. 5A and 5B) of the gas distribution plate 500 at step 494. Invarious embodiments, the gaseous mitigation agent is configured to mixwith the reaction gas downstream of the gas distribution plate 500, asdescribed in greater detail immediately below.

In various embodiments, and with reference to FIGS. 5A and 5B, the gasdistribution plate 500 includes a body 510 having a first side 511 and asecond side 512 opposite the first side 511. The body 510 may have anddefine an internal cavity 514. In various embodiments, a plurality ofpass-through tubes 520 extend through the internal cavity 514. Saiddifferently, each pass-through tube 520 of the plurality of pass-throughtubes extends from a first opening 521 defined in the first side 511 ofthe body 510 to a second opening 522 defined in the second side 512 ofthe body 510. The reaction gas that results from the chemical vapordeposition/infiltration process in the inlet portion 312 of the chamber310 (i.e., the reaction product(s) of the gaseous precursor) isconfigured to flow through the plurality of pass-through tubes 520, inaccordance with various embodiments. The gaseous mitigation agent,according to various embodiments, is configured to flow into theinternal cavity 514 via a cavity inlet 530, which may be coupled influid receiving communication with second inlet 330 (FIGS. 3A and 3B).The gas distribution plate 500 may further include a plurality of cavityoutlets 540 defined in the second side 512 of the body 510 through whichthe gaseous mitigation agent flows out of the internal cavity 514.Accordingly, the intermixing of the gaseous mitigation agent with thereaction gas is facilitated by distributing the second openings 522 ofthe plurality of pass-through tubes 520 among the cavity outlets 540.

In various embodiments, the reaction gas configured to flow through theplurality of pass-through tubes 520 is isolated from the gaseousmitigation agent in the internal cavity 514. That is, the reaction gasand the gaseous mitigation agent may not mix within the internal cavity514, but instead may be configured to mix downstream of the second side512 of the body 510 of the gas distribution plate 500. In variousembodiments, and with continued reference to FIGS. 5A and 5B, the body510 of the gas distribution plate 500 further includes a conicaldistribution feature 550 that protrudes into the internal cavity 514from the second side 512 of the body 510 opposite the cavity inlet 530.The conical distribution feature 550 may facilitate radially outwardflow of the gaseous mitigation agent, thereby promoting distribution ofthe gaseous mitigation agent through the plurality of cavity outlets540. In various embodiments, the body 510 of the gas distribution plate500 does not have any cavity outlets 540 or pass-through tubes 520positioned in the footprint of the conical distribution feature 550.That is, the region of the body 510 that falls within the footprint ofthe conical distribution feature 550 may be solid and may be free ofpass-through tubes, openings, apertures, etc. In various embodiments,the plurality of cavity outlets 540 and the second openings 522 of theplurality of pass-through tubes 520 are disposed outward of thefootprint of the conical distribution feature 550 and may be distributedcircumferentially around the conical distribution feature 550.

In various embodiments, and with reference to FIG. 6, the gasdistribution plate 500 may further include a plurality of static mixingfeatures 560 extending from the second side 512 of the body 510 of thegas distribution plate 500. The static mixing features 560, definedherein as non-moving, fixed elements, may be shaped and configured toaugment mixing of the gaseous mitigation agent with the reaction gas.Said differently, the plurality of static mixing features facilitatesintermixing of the gaseous mitigation agent with the reaction gas. Invarious embodiments, the static mixing features 560 may be “T” shaped.The static mixing features 560 may extend from the second side 512 ofthe body 510 of the gas distribution plate 500 adjacent the cavityoutlets 540.

In various embodiments, and with reference to FIGS. 7A and 7B, a dualplate system 50 is provided. The dual plate system 50 includes,according to various embodiments, a first gas distribution plate 500Aand a second gas distribution plate 500B. The dual plate system 50 maybe incorporated and utilized with a system of manufacturing a ceramicmatrix composite, such as the system of FIGS. 3A and 3B. The first gasdistribution plate 500A may be upstream of the second gas distributionplate 500B. For example, the second gas distribution plate 500B may bedisposed between the first gas distribution plate 500A and the outletportion 313 of the chamber 310.

The first gas distribution plate 500A may have a first body 510A havinga first side 511A and a second side 512A. The first body 510A of thefirst gas distribution plate 500A may define a first internal cavity514A, and a first plurality of pass-through tubes 520A may extendthrough the first internal cavity 514A from first openings 521A definedin the first side 511A of the first body 510A to second openings 522Adefined in the second side 512A of the first body 510A. Similarly, thesecond gas distribution plate 500B may have a second body 510B having afirst side 511B and a second side 512B. The second body 510B of thesecond gas distribution plate 500B may define a second internal cavity514B, and a second plurality of pass-through tubes 520B may extendthrough the second internal cavity 514B from first openings 521B definedin the first side 511B of the second body 510B to second openings 522Bdefined in the second side 512B of the second body 510B.

The gaseous mitigation agent may be configured to flow into the internalcavity 514A via cavity inlet 530A (which may be coupled to or acomponent of second inlet 330). The gaseous mitigation agent may beconfigured to be distributed throughout the internal cavity 514A of thebody 510A of the first gas distribution plate 500A. Instead of thegaseous mitigation agent flowing directly out of the internal cavity514A to be mixed directly with the reaction gas flowing through theplurality of pass-through tubes 520, the gaseous mitigation agent mayinstead flow from the internal cavity 514A via a plurality of secondcavity inlets 530B that extend between and fluidly couple the firstinternal cavity 514A of the first body 510A of the first gasdistribution plate 500A to a second internal cavity 514B defined in thesecond body 510B of the second gas distribution plate 500B. The firstcavity inlet 530A may be a central conduit and the plurality of cavityinlets 530B may be offshoot conduits that are positioned around thecentral conduit. In various embodiments, the first body 510A of thefirst gas distribution plate 500A may not have cavity outlets, such ascavity outlets 540 described above with reference to FIGS. 3A and 3B,defined in the second side 512A of the first body 510A of the first gasdistribution plate 500A. Thus, the gaseous mitigation agent may flowsequentially through both the first internal cavity 514A and the secondinternal cavity 514B before mixing with the reaction gas. Such aconfiguration provides allows the reaction gas to flow through twostages of pass-through tubes 520A, 520B before mixing with the gaseousmitigation agent. The second gas distribution plate 500B may furtherinclude a plurality of static mixing features 560 (e.g., described abovewith reference to FIG. 6).

In various embodiments, and with reference to FIG. 8, another dual platesystem 60 is provided. The dual plate system 60 includes, according tovarious embodiments, a first gas distribution plate 600A and a secondgas distribution plate 600B. The dual plate system 60 may be similar todual plate system 50 described above, and may accordingly beincorporated and utilized with a system of manufacturing a ceramicmatrix composite, such as the system of FIGS. 3A and 3B. The first gasdistribution plate 600A may have a first body 610A having a first side611A and a second side 612A. The first body 610A of the first gasdistribution plate 600A may not define an internal cavity (i.e., may notbe hollow) and instead may be solid, except for a first plurality ofpass-through tubes 620A may extend through the first body 610A from thefirst side 611A of the first body 610A to the second side 612A of thefirst body 610A. The second gas distribution plate 600B may have asecond body 610B having a first side 611B and a second side 612B. Thesecond body 610B of the second gas distribution plate 600B may define aninternal cavity 614B, and a second plurality of pass-through tubes 620Bmay extend through the internal cavity 614B from first openings 621Bdefined in the first side 611B of the second body 610B to secondopenings 622B defined in the second side 612B of the second body 610B.In such a configuration, the gaseous mitigation agent may flow throughthe first gas distribution plate 600A via central pass-through conduit630A and flows to the internal cavity 614B of the second gasdistribution plate 600B via one or more offshoot conduits 630B that arepositioned around the central conduit 630A. The gaseous mitigation agentis then distributed throughout the internal cavity 614B of the secondgas distribution plate 600B and then flows out of the internal cavity614B via a plurality of cavity outlets 640 to mix with the reaction gasthat passed through the two stages of pass-through tubes 620A, 620B. Thesecond gas distribution plate 600B may further include a plurality ofstatic mixing features 560 (e.g., described above with reference to FIG.6).

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure.

The scope of the disclosure is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” It is to be understood that unlessspecifically stated otherwise, references to “a,” “an,” and/or “the” mayinclude one or more than one and that reference to an item in thesingular may also include the item in the plural. All ranges and ratiolimits disclosed herein may be combined.

Moreover, where a phrase similar to “at least one of A, B, and C” isused in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C. Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

The steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Elements and steps in the figuresare illustrated for simplicity and clarity and have not necessarily beenrendered according to any particular sequence. For example, steps thatmay be performed concurrently or in different order are illustrated inthe figures to help to improve understanding of embodiments of thepresent disclosure.

Any reference to attached, fixed, connected or the like may includepermanent, removable, temporary, partial, full and/or any other possibleattachment option. Additionally, any reference to without contact (orsimilar phrases) may also include reduced contact or minimal contact.Surface shading lines may be used throughout the figures to denotedifferent parts or areas but not necessarily to denote the same ordifferent materials. In some cases, reference coordinates may bespecific to each figure.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment,” “an embodiment,”“various embodiments,” etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A system comprising: a chamber comprising aninlet portion and an outlet portion, wherein the inlet portion isconfigured to house a porous preform; a first inlet for introducing agaseous precursor into the inlet portion of the chamber; a first gasdistribution plate disposed between the inlet portion and the outletportion of the chamber, the first gas distribution plate defining afirst internal cavity; a second gas distribution plate disposed betweenthe first gas distribution plate and the outlet portion of the chamber,the second gas distribution plate defining a second internal cavity; asecond inlet for introducing a gaseous mitigation agent into the firstinternal cavity defined in the first gas distribution plate, wherein thefirst gas distribution plate and the second gas distribution plate areconfigured such that the gaseous mitigation agent is configured tosequentially flow through both the first internal cavity and the secondinternal cavity before mixing with a reaction gas from the inlet portionof the chamber; and an exhaust conduit coupled in fluidic communicationwith the outlet portion of the chamber.
 2. The system of claim 1,wherein the first gas distribution plate is configured to distribute thegaseous mitigation agent through the first internal cavity before thegaseous mitigation agent flows into the second internal cavity of thesecond gas distribution plate, wherein the second gas distribution platecomprises a plurality of pass-through tubes, wherein the second gasdistribution plate facilitates mixing the gaseous mitigation agent withthe reaction gas from the plurality of pass-through tubes.
 3. The systemof claim 1, wherein the second inlet is configured to introduce thegaseous mitigation agent into the first internal cavity via a firstcavity inlet, wherein the gaseous mitigation agent is configured to flowfrom the first internal cavity to the second internal cavity via aplurality of second cavity inlets extending between the first gasdistribution plate and the second gas distribution plate.
 4. The systemof claim 3, wherein the first cavity inlet is a central conduit and theplurality of second cavity inlets are offshoot conduits that arepositioned around the central conduit.